1. Field of the Invention
This invention relates to improvements in emergency brakes and more specifically to improvement in emergency brakes of the skid type including an elongated flexible skid member which may be held in a retracted position or moved into an extended position beneath a vehicle wheel by means of a motorized control mechanism to effect emergency braking of a vehicle.
2. Description of the Prior Art
Various types of emergency brake mechanisms for vehicles have heretofore been designed and used with varying degrees of success. Some of these emergency brakes are provided for engagement with various portions of the drive train of a vehicle and are most ineffective unless there is a failure of the drive train between the emergency brake mechanism and the support wheels of the vehicle. If such a failure does occur, the support wheels of the vehicle are then free wheeling and incapable of stopping forward movement of the vehicle.
Accordingly, certain emergency brake assemblies have been proposed which rely solely upon the rolling contact of one of more of the vehicle wheels with the supporting surface. Such emergency brakes include that shown in U.S. Pat. No. 3,078,963, issued Feb. 26, 1963 to Shea. The Shea patent shows an elongated flexible skid member which is maintained in a support tray which is disposed above a vehicle wheel. Upon actuation, the tray drops down upon the wheel and vibratory motion created by the wheel together with the force of gravity causes the skid to slide to a position beneath the wheel. Such a mechanism may be less than desirable in that the force of gravity constitutes the major means of causing initial movement of the skid. If the emergency brake has not been used for long periods of time, the skid may become stuck within its support tray and thus causing the emergency brake to be ineffective. Also, the vibrating motion created by engagement of the support tray with the wheel may cause undesirable side effects such as damage to the skid at the point of contact with the vehicle wheel.
Other emergency brake devices include U.S. Pat. Nos. 2,887,185, issued May 19, 1959 to Lee, 2,868,333, issued Jan. 13, 1959 to Willison, 2,818,939, issued Jan. 7, 1958 to Benn, 2,806,556, issued Sept. 17, 1957 to Norris, and 2,746,570, issued May 22, 1956 to Stahmer. Each of these devices, however, also relies upon the force of gravity for actuation thereof and in that respect, has some of the inherent deficiencies of the Shea patent.